FirebaseFirestore Framework Reference

FIRSetOptions

@interfaceFIRSetOptions:NSObject

An options object that configures the behavior of setData() calls. By providing the
FIRSetOptions objects returned by merge:, the setData() methods in FIRDocumentReference,
FIRWriteBatch and FIRTransaction can be configured to perform granular merges instead
of overwriting the target documents in their entirety.